CSSTidy is an opensource CSS parser and optimiser. It is available as executeable file (available for Windows, Linux and OSX) which can be controlled per ...
and removes all the rules and styles that are no longer necessary. Additionally, it tries to validate the stylesheets and exports ERRORS / WARNINGS detected ...
CSSTidy is a CSS minifier. css_optimiser.php is the web-interface; class.csstidy.php is the parser; bin/pcsstidy is the standalone command line executable.
A CSS optimizer and compressor tool is designed to improve the efficiency and speed of a website by minimizing the size of CSS (Cascading Style Sheets) files.